Cooler for electronic devices

ABSTRACT

An apparatus and method for a centrifugal pump ( 1 ) for pumping sensitive biological fluids which includes (i) an integral impeller and rotor ( 21 ) which is entirely supported and rotated magnetically by electromagnets ( 52, 54 ), (ii) a pump housing ( 12, 14 ) and arcuate passages for fluid flow and containment, (iii) a brushless driving motor ( 40 ) embedded and integral with the pump housing ( 12, 14 ), (iv) a power supply and (v) specific electronic sensing and control algorithms-all fitly jointed together to provide efficient, durable and low maintenance pump operation. A specially designed impeller ( 21 ) and pump housing ( 12, 14 ) provide the mechanism for transport and delivery of fluid through the pump to a pump output port with reduced fluid turbulence.

FIELD OF THE INVENTION

The invention covered by this application is related to devices intendedfor cooling electronic devices by removing heat by a flow of gas, inparticular, air flow, said flow being produced by a blower.

BACKGROUND OF THE INVENTION

The most widespread devices are the ones that comprise a heat exchangerrepresented by a heat sink, on one surface of which an electronic device(for instance, semiconductor device or computer processor) is installed,while another surface is made in the form of heat dissipating surface.The airflow is produced by a blower (axial fans may serve as a blower).

There are known devices of this type—see, for example, U.S. Pat. No.5,867,365 “CPU heat sink assembly” published on Feb. 2, 1999 (prioritydate—Jun. 10, 1997), Int.Cl. H05K 7/20, and U.S. Pat. No. 5,661,638“High performance spiral heat sink” published on Aug. 26, 1997 (prioritydate—Nov. 3, 1995), Int.Cl. H05K 7/20.

The design of the device described in U.S. Pat. No. 5,867,365 comprisesan axial fan that produces a flow passing by heat exchanging channels ofthe heat sink. The majority of inlets to heat exchanging channels arelocated just opposite the axial fan's impeller with a certain number ofsaid channels being placed radially in relation to fan axle.

U.S. Pat. No. 5,661,638 also involves the application of an axial fan.Specific embodiment of device claimed in said patent involves suchplacement of heat exchanging channels of the heat sink that they arelocated centrally-symmetrically about the fan axle. To increase the heatexchange area, the heat exchanging channels are made of spiral-likeshape and bent backwards in the direction of blower rotation. In thiscase the fan is installed in a recess made in the heat sink body.

In the above-mentioned designs, the axial fan produces sufficiently highair pressure. However, due to the weak airflow in the area adjacent tofan axle, the conditions for cooling the central part of the heat sinklocated underneath the fan are unfavorable. In this case non-uniformcooling of the heat sink and electronic device (in our case, processor)will take place. Besides, the energy of airflow outgoing from fanimpeller in the axial direction is expended on deceleration and turn inmotion before this airflow enters the heat exchanging channels. Thisfact decreases the speed of airflow passing by the heat exchangingchannels, which, in its turn, doesn't allow to obtain good conditionsfor heat exchange process.

Centrifugal blowers are used much more rarely in the cooling devicedesigns for the purpose of producing airflow.

Specifically, U.S. Pat. No. 5,838,066 “Miniaturized cooling fan typeheat sink for semiconductor device” published on Nov. 17, 1998 (prioritydate—Dec. 16, 1996), Int.Cl. H05K 7/20 offers a design employing acentrifugal blower that is installed to the side of the heat sink. Inone particular embodiment of this invention the cooling airflow passesby rectilinear heat exchanging channels of the heat sink.

However, placement of centrifugal blower to the side of the heat sinkincreases device size. This is so because such location of centrifugalblower leads to insufficient coordination between the direction ofchannel inlets and direction of airflow supplied from the blower. Theloss in airflow energy results in the reduction of airflow motion speedin heat exchanging channels and in the decline of heat exchangeefficiency. A portion of energy is also expended on friction against thecasing, in which the blower is enclosed.

The closest analogue to the invention being claimed is an inventiondescribed in the patent of Japan No 8-195456 entitled “Cooler forelectronic apparatus” (priority date—Jan. 17, 1995; application forpatent published on Jul. 30, 1996; Int.Cl. H01L 023/467).

Device design comprises a centrifugal fan enclosed in the casing andinstalled above the heat exchanging channels that are made divergent.Another heat sink surface is made so that the possibility of thermalcontact with an electronic device is provided for. The inlet of thecentrifugal fan faces the heat sink. The fan produces an airflow thatpasses by heat exchanging channels and then gets sucked into the inletof the centrifugal fan.

Since the centrifugal fan operates by suction, there is an area in thecentral part of the heat sink that is poorly blown around by the airflow(which could be seen from the Fig. presented in the published patent).Therefore, cooling of the heat sink's central part, which is thehottest, is performed ineffectively. This disadvantage results in theuneven cooling of the heat sink. To avoid uneven cooling of the heatsink, one has to raise the fan power. In addition, the device is ofquite considerable height because the centrifugal fan is placed abovethe heat sink.

SUMMARY OF THE INVENTION

The engineering problem to be solved with the help of the inventionbeing claimed herein is the development of a cooler for electronicdevices that ensures more uniform cooling of electronic devices due tomore effective cooling of the central part of the heat exchange elementand the reduction of cooling device size.

Two options of addressing this problem are being claimed.

The essence of the invention in conformity with the first optionconsists in the following.

A cooler for electronic devices comprises a heat exchange element (i.e.heat sink) with divergent heat exchanging channels made on its one side,while its other side is made so that a possibility of thermal contactwith an electronic device is provided for, and a centrifugal blowerinstalled on the heat exchange element in such a way that it providesfor the passing of cooling flow by heat exchanging channels.

The centrifugal blower is installed in the center of symmetry of heatexchanging channels. It supplies cooling flow (for instance, airflow) tothe central part of heat exchange element. Since the blower impeller islocated right opposite the inlets of said heat exchanging channels, thecooling flow is then supplied to channel inlets and as it moves by saidchannels it cools the heat exchange element down.

Since the centrifugal blower is installed at the same level as the heatexchanging channels are, the size of the device in height is reduced andthe cooling flow is directed into the heat exchanging channels withoutenergy expenditures on turning the flow (from axial direction to theradial direction). The latter is explained by the fact that flow turn iseffected owing to the properties of centrifugal blower design.

The above-mentioned specific features of the device claimed hereinprovide for a special cooling pattern, which is characterized by thefact that the hottest part of the heat exchange element (namely, itscentral part) gets cooled first, and, as compared to the above-describedprototype, the entire cooling process proceeds more evenly and withoutlosses that are caused in said prototype by flow turn and friction whenthe cooling flow (going from the impeller) enters the heat exchangingchannels. As a consequence, when using the invention being claimed onewould need a blower of lesser power and size.

It is advisable that centrifugal blower be equipped with an impeller ofdrum type. In this case the impeller has wide enough suction hole thatmakes it possible to produce a powerful enough flow to cool the centralpart of the heat exchange element well. Besides, for a given blowercapacity, a centrifugal blower with a drum-type impeller has minimalsize and rotational speed as compared to centrifugal blowers with animpeller of other type.

For the purpose of increasing heat exchange area, the heat exchangingchannels can be made in the form of rows of profiled elements. Inparticular, these elements can me made in the form of needles.

As a particular embodiment of the invention, the heat exchangingchannels may be made spiral-like and bent in the direction ofcentrifugal blower rotation. This will provide for the prolonged contactbetween the airflow and heat exchange element surface.

In addition, the heat exchanging channels may be made of constant width.This will make it possible to ensure the constancy of speed at which theairflow blows the surfaces of heat exchanging channels over. Besides,making heat exchanging channels of constant width would enable one toattain the maximum “density” of heat exchanging channels on the heatexchange element surface, which would result in obtaining greater heatexchange area.

When making heat exchanging channels spiral-like or of constant width itis advisable to orient their inlets in the direction of propagation ofthe output flow produced by centrifugal blower impeller. In this casethe best matching between the channels and incoming airflow is attained,which, in its turn, would sustain the airflow speed at the maximumpossible level.

To attain improved heat exchange in the central part of the heatexchange element, the surface underneath the suction hole of thecentrifugal blower may be made needle-shaped. This part of the heatexchange element is in essence located inside the centrifugal blower—inthe area of the main airflow. With such an arrangement of the heatexchange element there will be practically no extra losses for theflowing over the needles, while heat exchange will be improved.

Making heat exchange element underneath the blower bent out will raisethe efficiency of heat exchange. Since the centrifugal blower isinstalled at the same level as the heat exchanging channels are, thecooling flow is directed to the heat exchanging channels without energyexpenditures spent on the turn of the flow (from axial direction to theradial direction). This flow turn is made owing to the features ofcentrifugal blower design and shape of the heat exchange elementunderneath the blower. Bent part of the heat exchange element located inthe central part of blower impeller has greater heat exchange surface ascompared to the case when heat exchange element is made flat. Besidesradial velocity component, the airflow passing along the side conicalsurface of the bent part of the heat exchange element has additionaltangential velocity component. Thus, due to the fact that the speed atwhich the heat exchange surface is blown around is increased the extrarise in heat exchange efficiency is attained. In addition, the distancebetween the bent surface and blower inlet is decreased in this case,which fact facilitates the increase in the airflow speed in the gapbetween the heat exchange element and blower impeller, thus giving extragain in cooling efficiency.

Small height of the device claimed herein represents another importantengineering accomplishment. Semiconductor device or processor isinstalled in the recess formed by the concave part of the heat exchangeelement. This concave part of the heat exchange element goes into thecentral part of blower impeller, which fact also decreases the size.

The above-indicated specific features of device design results in thefact that cooling flow is supplied first to the central part of the heatexchange element, which is the hottest part. Cooling of this partproceeds more evenly and without losses expended on flow turn andfriction when the cooling flow (going from the impeller) enters the heatexchanging channels. As a consequence, when using the present inventiondesign with a bent central part of the heat exchange element one wouldneed a blower of lesser power and size.

For the purpose of improving heat exchange, the surface of the bent partof the heat exchange element (i.e. the surface facing the inlet openingof the centrifugal blower) may be made profiled in such a way that adeveloped heat exchange surface is produced (for instance, needle-shapedsurface), e form of rows of profiled elements. This part of the heatexchange element is in essence located inside the centrifugal blower—inthe area of the main airflow. With such an arrangement of the heatexchange element there will be practically no extra losses for theflowing over the needles, while heat exchange will be considerablyimproved.

To prevent additional noise caused by the pulsation of pressure of thecooling flow at the inlets of the heat exchanging channels, it isadvisable to install the centrifugal blower impeller with a radial gapof no less than 0.03 d (where d is the diameter of centrifugal blowerimpeller) in relation to the inlets of the heat exchanging channels.

The heat exchanging channels may be covered with a plate from above. Inthis case the cooling airflow will propagate only along the channels.

The cooler for electronic devices in conformity with the second optionis made as follows.

The device comprises a heat exchange element (i.e. heat sink) withdivergent heat exchanging channels made on its one side, while its otherside is made so that a possibility of thermal contact with an electronicdevice is provided for, and a centrifugal blower installed on the heatexchange element in such a way that it provides for the passing ofcooling flow by heat exchanging channels.

A disk-type centrifugal blower with at least one disk is used in thedesign. The disks are installed in such a manner that the edge of disksurface facing the heat exchange element is located opposite the inletsto the heat exchanging channels.

The centrifugal blower supplies cooling flow (for instance, airflow) tothe central part of the heat exchange element, which fact facilitatesthe effective cooling of the hottest part of the heat exchange element.Transfer of energy from blower disk to the airflow proceeds due to thefriction forces.

The airflow blows the central part of the heat exchange element over notonly in the radial direction, but also in the tangential one, due towhich fact an additional increase in airflow speed in the central partof the device takes place and extra gain in cooling efficiency isattained.

Since the edges of blower disk surfaces facing the heat exchange elementare located opposite the inlets to the heat exchanging channels, thecooling flow is supplied to said inlets and as the airflow passes by thechannels it cools the heat exchange element down. The disk-typecentrifugal blower generates radial component of the cooling flow, andsaid radial component matches the inlets to the heat exchanging channelswell.

The disk-type centrifugal blower is characterized by small size (interms of height) while being effective enough. In addition, it is alsocharacterized by minimal noise level as compared to other types ofcentrifugal blowers, all other factors being equal.

The above-mentioned specific features of the device claimed hereinprovide for a special cooling pattern, which is characterized by thefact that the hottest part of the heat exchange element (namely, itscentral part) gets cooled first, and, as compared to the above-describedprototype, the entire cooling process proceeds more evenly and withoutlosses that are caused in said prototype by flow turn and friction whenthe cooling flow (going from the blower disk) enters the heat exchangingchannels. As a consequence, when using the invention being claimed onewould need a blower of lesser power and size.

In addition, the surface of at least one of the disks of the disk-typecentrifugal blower (facing the heat exchange element) may be equippedwith radial fins that increase the radial component of the airflow.

Besides, axial blower blades may be installed on at least one of thedisks of the centrifugal blower near its central opening, said bladesbeing attached to the disk. The blades may be installed on one disk oron several disks. Installation of axial blower blades near the centralopening of the disk increases the pressure of cooling airflow in thecentral part of the heat exchange element with the blower capacity beingthe same. Such a design of the disk-type centrifugal blower coupled withinstallation of axial blower blades makes it possible to attain the sameblower capacity with a lower number of revolutions, which fact resultsin additional decrease in noise level generated by the blower.

According to one of the design options, the axial blower blades may beformed by straps that secure disk on the axle of the centrifugal blower.

The heat exchange element underneath the blower may be made bent in thedirection to the blower so that the bent part of the heat exchangeelement is located underneath the inlet of disk blower. In this case theoverall size of the device is reduced (because an electronic device fitsinto the recess) and cooling process is improved (because the hottestcentral part is blown over with a portion of flow passing at a higherspeed).

For the purpose of increasing the heat exchange area, the heatexchanging channels can be made in the form of rows of profiledelements. In particular, these elements can me made in the form ofneedles.

As a particular embodiment of the invention, the heat exchangingchannels may be made spiral-like and bent in the direction ofcentrifugal blower rotation. This will provide for the prolonged contactbetween the airflow and heat exchange element surface.

In the latter case the heat exchanging channels may be made of constantwidth. This will make it possible to ensure the constancy of speed atwhich the airflow blows the surfaces of heat exchanging channels over.Besides, making heat exchanging channels of constant width would enableone to attain the maximum “density” of heat exchanging channels on theheat exchange element surface, which would result in obtaining greaterheat exchange area

When making heat exchanging channels spiral-like (including the casewhen they are made of constant width) it is advisable to orient theirinlets in the direction of the propagation of the output flow producedby centrifugal blower. In this case the best matching between thechannels and incoming airflow is attained, which, in its turn, wouldsustain the airflow speed at the maximum possible level.

To attain improved heat exchange, the surface of the heat exchangeelement part facing the inlet of the centrifugal blower may be madeprofiled in such a way that a developed heat exchange surface isproduced (for instance, it may be made needle-shaped). This part of theheat exchange element is located in the area of the main airflow.Therefore, it gets cooled effectively. With such an arrangement of theheat exchange element there will be practically no extra losses for theflowing over the needles, while heat exchange will be considerablyimproved.

In addition, from the inside, the heat exchanging channels may becovered with a plate from above secured to the surface of the heatexchange element. In this case the entire cooling airflow will propagateonly along the channels, which fact also facilitates the improved heatexchange.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1—general view of the first design option of the device claimedherein (with heat exchanging channels being arranged radially);

FIG. 2—a sample design of radially diverging heat exchanging channels;

FIG. 3—a sample design of radially diverging spiral-like heat exchangingchannels;

FIG. 4—a sample design of spiral-like heat exchanging channels ofconstant width;

FIG. 5—an illustration to geometric relationships needed for thecalculation of the profile of spiral-like heat exchanging channels ofconstant width;

FIG. 6—a sample design of heat exchanging channels formed by rowsneedle-shaped profiled elements;

FIG. 7—a sample design of the device with a centrifugal blower fixed tothe axle and a plate covering heat exchanging channels from the above;

FIG. 8—a cross-section of the claimed device shown in FIG. 7 (inaccordance with the first design option) with an impeller of a drum-typecentrifugal blower and a heat exchange element bent underneath theblower;

FIG. 9—a sample design of radial heat exchanging channels with a heatexchange element bent underneath the blower (in accordance with thefirst device design option);

FIG. 10—a sample design of the claimed device (in accordance with thesecond device design option) with a centrifugal blower having severaldisks:

FIG. 11—a sample design of radial heat exchanging channels of the heatexchange element (in accordance with the second device design option);

FIG. 12—a sample design of the claimed device (in accordance with thesecond device design option) with a centrifugal blower having one disk;

FIG. 13—a centrifugal blower disk;

FIG. 14—a sample design of the claimed device (in accordance with thesecond device design option) with a centrifugal blower disk, on whichradial fins are installed;

FIG. 15—a centrifugal blower disk with radial fins (bottom view);

FIG. 16—a sample design of the claimed device (in accordance with thesecond device design option) with a centrifugal blower disk, in the areaof the central opening of which axial blower blades are installed;

FIG. 17—a centrifugal blower disk with axial blower blades;

FIG. 18—a cross-section of the centrifugal blower disk shown in FIG. 17(in the area of axial blower blade).

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Below is described the first design option of the device claimed herein.

The cooler for electronic devices (FIG. 1 and FIG. 2) comprises a heatexchange element 101 with divergent heat exchanging channels 103 made onits one surface 102, while its other surface 104 is made so that apossibility of thermal contact with an electronic device (not shown inFIG. 1) is provided for. The device also comprises a centrifugal blower105 installed on the heat exchange element 101 in the center of symmetry106 in relation to heat exchanging channels 103.

FIG. 1 and FIG. 2 present radially diverging heat exchanging channels103. Impeller 107 of centrifugal blower 105 is placed opposite inlets108 of heat exchanging channels 103. Sample designs of centrifugalblower 105 having drum-type impeller 107 are shown in FIG. 6 and FIG. 9.Such drum-type centrifugal blowers are characterized by the fact thatthe value of the relation of impeller inner diameter to its outerdiameter is no less than 0.75.

In the device claimed herein (see FIG. 3) heat exchanging channels 103may be made spiral and bent over in the direction of rotation ofcentrifugal blower 105.

One more embodiment of device design (see FIG. 4) is characterized bythe fact that heat exchanging channels 103 are of constant width.

In the embodiments of device design presented in FIG. 3 and FIG. 4,inlets 108 of heat exchanging channels 103 are oriented in the directionof propagation of the output flow produced by impeller 107 ofcentrifugal blower 105. It is best to orient the inlets of heatexchanging channels in such a way that the angle between the axis ofheat exchanging channel inlets and the direction of incoming airflowproduced by impeller 107 will lie within the range ±5° (see FIG. 5).

FIG. 5 shows heat exchanging channel 103 formed by two fins 109 (arc ABand arc CD) and corresponding geometric constructions needed for thecalculation of the profile of heat exchanging channels of constantwidth. For an arbitrary point E of arc AB located at distance r fromcenter of symmetry O and point F (corresponding to said point E) of arcCD [the distance between two said points t(r) represents the width ofheat exchanging channel], point G of arc CD located also at distance rfrom the center of symmetry O is determined. Distance a(r) between pointE and point G for a great number of heat exchanging channels Z isapproximately equal to the length of arc EG—i.e. a(r)≈2πr/Z. Under thesame conditions the value of t(r) may be defined as t(r)≈a(r)·sin[b(r)].Using numeric methods it is possible to calculate for t(r)=T (whereT=const) the values of angle b(r), thus determining the profile of aheat exchanging channel. In particular, FIG. 4 present an example ofsample design with a number of heat exchanging channels Z=22 andrelationship between minimal distance r=r₀ (point A) and maximumdistance r=r_(k) (point B): r₀=0,4r_(k). For the given case, the valuesof angle b(r) were determined, said values being within the range fromb(r₀)=34,22° to b(r_(k))=13,0°.

To improve heat exchange process, the surface of heat exchange element101 located underneath the suction inlet of centrifugal blower 105 (asshown in FIG. 1) is made needle-shaped, where 110—are needles.

In relation to inlets 108 of heat exchanging channels 103 impeller 107of centrifugal blower 105 is installed with radial gap 111, the value ofwhich is no less than 0.33 d, where d is the diameter of impeller 107 ofcentrifugal blower 105.

Heat exchanging channels 103 may be formed by the rows of profiledelements of circular, rectangular and other cross section. The saidprofiled elements may be made so that they are located immediatelyadjacent to one another (as shown in FIG. 6) where they are made in theform of needles 112. Besides, these profiled elements may be produced bymaking saw cuts in solid fins that make up channels 103 (for instance,in fins 109—see FIG. 4).

For all above-presented embodiments, heat exchange element 101 may bemade by different methods (for instance, by casting or milling).

Centrifugal blower 105 may be secured to axle 113 by means of bearing114 (see FIG. 7). To ensure that the entire forced airflow passes byheat exchanging channels 103, the latter are covered by plate from theabove. In this case plate 115 locks axle 113 by means of straps 116.

In one of the embodiments of the invention (see FIG. 8 and FIG. 9), thecentral part 117 of heat exchange element 101 located underneath blower105 is made bent over. Bent part 118 of heat exchange element 101 islocated opposite the centrifugal blower inlet 106—in the central part117 of impeller 108.

The claimed device in accordance with the first design option operatesin the following manner.

When impeller 107 of centrifugal blower 105 rotates (see FIG. 1) theairflow at first blows over the central part of heat exchange element101, including its needles 110. Intensive heat exchange proceeds in thisarea of heat exchange element 101, which is the hottest area of saidheat exchange element. Impeller 107 of centrifugal blower 105 suppliesthe airflow to inlet 108 of heat exchanging channels 103. In the casewhen heat exchanging channels 103 are made spiral-like and bent in thedirection of rotation of blower 105 (see FIG. 3 and FIG. 4) the airflowis directed to channels 103 without deceleration, which means that thereis no loss in airflow speed when it enters channel 103. The airflowspeed in heat exchanging channels 103 of constant width (see FIG. 4) iskept constant. Heat exchange between heat exchange element 101 andairflow takes place when the latter passes by heat exchanging channels103. As a result of this heat exchange process, an electronic devicebeing in thermal contact with heat exchange element 101 gets cooleddown.

With bent central part 118 of heat exchange element 101 (FIG. 8 and FIG.9), in addition to radial velocity component, the airflow passing alongthe side conical surface of the bent part of heat exchange element hasadditional tangential velocity component. Thus, due to the fact that thespeed at which the heat exchange surface is blown over is increased thegrowth in airflow speed in the gap between exchange element 101 andimpeller 107 of blower 105 is attained, which results in extra rise inheat exchange efficiency.

Below is described the second design option of the device claimedherein.

The cooler for electronic devices (FIG. 10 and FIG. 11) comprises a heatexchange element 201 with divergent heat exchanging channels 203 made onits one surface 202, while its other surface 204 is made so that apossibility of thermal contact with an electronic device 205 is providedfor. The device also comprises a centrifugal blower 206 installed on theheat exchange element 201 in such a manner that that it provides for thepassing of cooling flow by heat exchanging channels 203.

A disk-type centrifugal blower 206 with at least one disk 207 is used inthe design. FIG. 10 presents a sample design of centrifugal blower 206with four disks 207. Disks 207 are installed in such a manner that theedge 208 of each disk surface facing the heat exchange element 201 islocated opposite inlets 209 to the heat exchanging channels 203. A crosssection of the device having radial heat exchanging channels 203 isshown in FIG. 11.

A design option of centrifugal blower 206 with one disk 207 is shown inFIG. 12. In this case heat exchange element 201 may be made of smallheight.

A design option of disk 207 with radial straps 212, with the help ofwhich disk 207 is secured to axle 213 of blower 206, is shown in FIG.13.

The surface of disk 207 facing heat exchange element 201 may be equippedwith radial fins 210 (see FIG. 14 and FIG. 15).

Heat exchange element 201 underneath the blower may be made bent—as isshown in FIG. 14—in such a manner that the bent part of heat exchangeelement is located opposite the central opening 205 of disk 207 ofcentrifugal blower 206.

Axial blower blades 211 fixed to disk 207 (see FIG. 16 and FIG. 17) maybe installed in the area of central opening 215 of disk 207. FIG. 16presents an example of device embodiment with blades 211 installed onone disk 207. In this case blades 211 may also serve as straps 212securing disk to axle 213 of blower 206.

As with the first design option of the invented device the divergentheat exchanging channels may be made spiral-like (see FIG. 3). Inaddition, heat exchanging channels may be made of constant width (seeFIG. 4). Heat exchanging channels may be formed by rows of profiledelements—for instance, needles (see FIG. 6).

The surface of the part of heat exchange element 201 located underneathinlet 215 of disk-type blower 206 may be made profiled (for instance,needle-shaped—as shown in FIG. 10-FIG. 12, FIG. 14 and FIG. 16, where216—needles).

For the purpose of producing an airflow directed along channels 203, itis advisable to cover heat exchanging channels 203 from the outside withplate 217 (see FIG. 10, FIG. 12, FIG. 14, and FIG. 16).

For all embodiments of the present invention, heat exchange element 101or 201 may be made by different methods—for instance, by casting ormilling

Centrifugal blower 206 can be secured to axle 213 (see FIG. 10, FIG. 12,FIG. 14, and FIG. 16) by means of bearing 219. In this case plate 217has an opening (intended to let the air pass through), Besides, plate217 secures axle 213 to heat exchange element 201.

The claimed device in accordance with the second design option operatesin the following manner.

When disks 207 of centrifugal blower 206 rotate (see FIG. 10) theairflow primarily blows over the central part of heat exchange element201, including its needles 216. Intensive heat exchange takes place inthis area of heat exchange element 201, which is the hottest area ofsaid heat exchange element. Disks 207 of centrifugal blower 206 supplythe airflow to inlet 209 of heat exchanging channels 203. In the casewhen heat exchanging channels 203 are made spiral-like and bent in thedirection of rotation of blower 206, the cooling airflow is directed tochannels 203 without deceleration, which means that there is no loss inairflow speed when it enters channel 203. The airflow speed in heatexchanging channels 203 of constant width (see FIG. 4) is kept constant.

Heat exchange between heat exchange element 201 and airflow takes placewhen the latter passes by heat exchanging channels 203. As a result ofthis heat exchange process, electronic device 205 being in thermalcontact with heat exchange element 201 gets cooled down.

The airflow produced by disk 207 propagates not only in radialdirection, but also in tangential direction. Fins 210 (FIG. 14 and FIG.15) installed on disk 207 augment the radial component of the airflow.

In the case when blades 211 of axial fan are installed in the area ofthe central opening 215 of disk 207 (FIG. 16-FIG. 18) said bladesproduce additional pressure of airflow, thus facilitating better coolingof the central part, and hence cooling of entire heat exchange element201.

The present invention may be used for the purpose of cooling electronicdevices (primarily—semiconductor devices), microcircuit chips andmicroprocessors.

Application of devices with a centrifugal blower, the impeller of whichis located opposite the inlets to heat exchanging channels for thepurpose of cooling electronic devices enables one to create effectiveand small-size devices for said purpose.

What is claimed is:
 1. A cooler for electronic devices comprising a heatexchange element and a centrifugal blower, said heat exchange elementhaving a first heat exchange surface and a second heat exchange surface,said first heat exchange surface having a plurality of continuous wallheat exchange channels and said second heat exchange surface beingadapted to provide thermal contact with an electronic device, saidcentrifugal blower being positioned on said first heat exchange surfacewith the periphery of said blower surrounded by said plurality ofcontinuous wall heat exchange channels whereby an outlet of saidcentrifugal blower is located opposite inlets of said plurality ofcontinuous wall heat exchange channels, said centrifugal blowercomprising a suction path positioned in a central part of said blowerand an impeller surrounding said suction path, said impeller beingoperable to draw cooling gas into said suction path to cool at least aportion of said first heat exchange surface which is in the vicinity ofsaid suction path and then to flow through said impeller which directssaid cooling gas into said plurality of continuous wall heat exchangechannels.
 2. The cooler of claim 1, wherein said centrifugal blower hasa drum type impeller.
 3. The cooler of claim 1, wherein said first heatexchange surface which is in the vicinity of said suction path comprisesa plurality of heat exchange elements which project into said suctionpath.
 4. The cooler of claim 3, wherein said plurality of heat exchangeelements are upwardly projecting rods.
 5. The cooler of claim 3, whereinthe heat exchanging channels are formed between adjacent rows ofupwardly projecting rods.
 6. The cooler of claim 4, wherein said rodsare cylindrical.
 7. The cooler of claim 1, wherein said heat exchangechannels are spiral channels which are curved in a direction of rotationof said blower.
 8. The cooler of claim 3, wherein said heat exchangechannels are spiral channels which are curved in a direction of rotationof said blower.
 9. The cooler of claim 7, wherein the inlets to the heatexchange channels are in the direction of outward gas flow from saidimpeller.
 10. The cooler of claim 7, wherein said heat exchange channelsare of constant width.
 11. The cooler of claim 10, wherein the inlets tosaid heat exchange channels are in the direction of outward gas flowfrom said impeller.
 12. The cooler of claim 2, wherein said first heatexchange surface which is in the vicinity of said suction path comprisesa plurality of heat exchange elements which project into said suctionpath.
 13. The cooler of claim 1, wherein said portion of said first heatexchange surface which is in the vicinity of said suction path ispositioned a distance from the inlet of the said suction path which isshorter than the distance from a top of the impeller to a bottom of theimpeller.
 14. The cooler of claim 13, wherein said second heat exchangesurface substantially follows the surface shape of said first heatexchange surface.
 15. The cooler of claim 13, wherein said portion ofsaid first heat exchange surface which is in the vicinity of saidsuction path comprises a plurality of heat exchange elements whichproject into said suction path.
 16. The cooler of claim 15, wherein saidplurality of heat exchange elements are upwardly projecting rods. 17.The cooler of claim 1, wherein the centrifugal blower impeller isinstalled with a radial gap of no less than 0.03 d (where d is thediameter of centrifugal blower impeller) in relation to the inlets ofthe heat exchange channels.
 18. The cooler of claim 1, wherein the heatexchange channels are covered with a plate from above said channels. 19.The cooler of claim 1, wherein said centrifugal blower is a disk-typeblower with at least one disk, and said at least one disk is positionedso that the edge of the disk facing the heat exchange element is locatedopposite the inlets to the heat exchange channels.
 20. The cooler ofclaim 19, wherein said first heat exchange surface which is in thevicinity of said suction path comprises a plurality of heat exchangeelements which project into said suction path.
 21. The cooler of claim20, wherein said plurality of heat exchange elements are upwardlyprojecting rods.
 22. The cooler of claim 19, wherein the surface of saidat least one disk that faces the heat exchange element has radialprojections.
 23. The cooler of claim 19, wherein said at least one diskis secured by connectors to the centrifugal blower axle in said suctionpath area.
 24. The cooler of claim 23, wherein said connectors are axialblower blades.
 25. The cooler of claim 19, wherein said portion of saidfirst heat exchange surface which is in the vicinity of said suctionpath is positioned a distance from the inlet of the said suction pathwhich is shorter than the distance from a top of the impeller to abottom of the impeller.
 26. The cooler of claim 25, wherein said secondheat exchange surface substantially follows the surface shape of saidfirst heat exchange surface.
 27. The cooler of claim 25, wherein theheat exchanging channels are formed between adjacent rows of upwardlyprojecting rods.
 28. The cooler of claim 27, wherein said rods arecylindrical.
 29. The cooler of claim 19, wherein said heat exchangechannels are spiral channels which are curved in a direction of rotationof said blower.
 30. The cooler of claim 29, wherein the inlets to theheat exchange channels are in the direction of outward gas flow fromsaid disk impeller.
 31. The cooler of claim 29, wherein said heatexchange channels are of constant width.
 32. The cooler of claim 31,wherein the inlets to said heat exchange channels are in the directionof outward gas flow from said disk impeller.
 33. The cooler of claim 19,wherein the heat exchanging channels are covered with a plate from abovesaid channels.